(Capcom's primary storyline)
Professor James Marcus  was a brilliant scientist who became one of the three founding members of the Umbrella Corporation, and creator of the original strain of the t-Virus. A brilliant and enthusiastic scientist, he held a dark reputation for unethical experiments and mysteriously disappeared in 1988.[notes 1]
Born in around 1918, Marcus befriended Edward Ashford during his studies at school, where he quickly proved himself an expert on biology and virology. After leaving school, Marcus and Ashford became research partners, and began pursuing research into the Progenitor virus, and enlisted the aid of one of Ashford's close friends: Lord Oswell E. Spencer, who provided enough funding that they discovered the virus in 1967.
Marcus and Spencer believed that it could be used to create a powerful biological weapon for military use, while Ashford was simply interested in his research, no matter what the consequences.
To mask their research and motives, the three scientists formed the Umbrella Corporation, drawing massive profits and political authorization for them to continue their research. All of their sinister intentions were camouflaged with the image of a benevolent, trustworthy and highly-respected pharmaceutical company, which itself soon gained prominence.
In 1968, Marcus reached the position of General Manager and Research and Development Director, and was appointed head of the Umbrella Research Center in the Arklay Mountains. While Ashford assisted him, Spencer took over the corporation's financial duties. Ashford died later that year after contracting the Progenitor virus.
Marcus continued his research into the virus, and in January 1978, managed to create the t-Virus by combining leech DNA with the Progenitor virus, which in turn would lead to further research into Progenitor and the later discovery of the G-Virus and creation of Umbrella's line of B.O.W.s. This remarkable find gave Marcus much attention and prestige from his fellow researchers, though Spencer, intimidated by his findings, began to grow increasingly paranoid of Marcus.
Later that same year, taking a break from his research, Marcus took two of his most promising researchers; William Birkin and Albert Wesker. While teaching them to be responsible scientists, Marcus intended to use his findings to gain a place on the company's Board of Directors. In July, before Marcus could present his findings, Spencer intervened, by officially closing down the Umbrella training facility and transferring the t-Virus project's development to the nearby Arklay Laboratory.
Continuing His Experiments
Even though the training facility was closed down, Marcus continued to work there. During the 1980s, Marcus was all but confined to the training facility. Continuing the virus' experimentation, such as creating the first "t"-based B.O.W.s (including the Plague Crawler, the Lurker, and the Eliminator), and learning of the t-Virus' potential. Soon, Marcus' isolation took its toll on him mentally, eventually using his own assistants as guinea pigs for his leech experiments.
Spencer's paranoia peaked, and he ordered Wesker and Birkin to assassinate Marcus while he least expected it. This occurred one day in 1988 when two Umbrella Security Service commandos stormed into Marcus' laboratory and gunned him down. Wesker and Birkin taunted Marcus while he bled to death. As the assailants departed, Marcus' body was disposed of, thrown in the waters of the facility's sewage plant. However, at the time of his assassination, Marcus was conducting an experiment on a live leech, which escaped from its containment unit after it was broken by gunfire. The leech entered his body via his mouth and bonded with his DNA, allowing him to slowly regenerate into something no longer human. In terms of appearance, Marcus was reborn with the physical characteristics of himself in his early 20s, young enough to be mistaken for Marcus' son or grandson.[notes 2] With time, Marcus learned to control and expertly manipulate the leeches, considering them his children.
Meanwhile, the assassination was kept quiet by Umbrella, particularly by Birkin and Wesker. Spencer engaged in a little revisionist history, claiming that he had discovered the t-Virus and Marcus was only working on it, before being "fired" (an obvious euphemism for his assassination to those privy to it) for abusing his power.
- See: Queen Leech
"However, something wondrous happened. It took the t-Virus ten years to procreate my new life. And I will have my revenge on Umbrella, and the world will burn in an inferno of hate!"
Over the next ten years, Marcus' "Queen Leech", which was dumped along with his body, gradually merged its body with his. It eventually revived him to some extent, having replicated his personality along with his body in a much better way than the "Mimicry Marcus" form other leeches would take. However, this form would eventually be undone by the time he/the Queen Leech fought Billy Coen and Rebecca Chambers, with any remaining traces of Marcus being destroyed when Coen took advantage of the Queen Leech's weakness to sunlight and shot her down an elevator and being caught in an inferno from the self-destruct sequence being activated. Wesker (who at that time had been trying to escape the Umbrella Executive Training Facility due to its impending destruction) later learned second-hand Marcus' transformation into the Queen Leech and, combined with his directly witnessing a similar mutation by Umbrella officer Sergei Vladimir at the Caucasus laboratory five years later, began to theorize a connection between the non-zombified infected host's mutation and their psychology.
- Capcom Production Studio 4. Resident Evil Zero. (2003)
- Hamamura, Koichi, ed (2003) (in Japanese). biohazard 0 KAITAISHINSHO. Famitsu. ISBN 4-7577-1298-7.
- Sumner, Christian; Shotten, Brian; Owen, Michael, eds (9 November 2005). Resident Evil Archives: Umbrella's Virus Uncovered. Translated by Zpang America, Inc.. BradyGames. ISBN 0744006554.
- ↑ Excerpt from biohazard 0 KAITAISHINSHO:
"アンブレラ幹部養成所の初代所長。アンブレラの創始者オズウェル・E・スペンサーの友人で、ともに始祖ウイルスを発見した者のひとりである。 科学者としては突出して優れていたが、 ウイルス研究に狂的なまでの情熱を傾け、社内の倫理を逸脱するほど残酷な実験を行なったことにより、内部からも危険視されていた。 10年前、 謎の失踪を遂げている。"
- ↑ Billy Coen and/or Rebecca Chambers, when finding the photo album containing photos of James Marcus's younger self, began suspecting that the man they were tailing was either James Marcus's son or grandson.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Sumner, Shotten, Owen (eds). Archives. p.130
- ↑ 2.0 2.1 2.2 2.3 2.4 Hamamura (ed.), KAITAISHINSHO, p.011
- ↑ 3.0 3.1 3.2 3.3 3.4 Resident Evil Zero (2002), file: "Marcus' Diary 1"
- ↑ Resident Evil Zero (2002), file: "B.O.W. Report"
- ↑ Resident Evil Zero (2002), file: "Investigator's Report"
- ↑ Capcom Production Studio 4. Resident Evil Zero. (Capcom). File: Leech Growth Records.
- ↑ Resident Evil: The Umbrella Chronicles (2007), file: "Wesker's Notes on Differing Mutations "